This invention relates to a connector for making connections of fiber-optic, electrical, and hybrid electro-optical cables in a hostile or underwater, high pressure environment.
There are many types of connectors for making electrical and fiber-optic cable connections in hostile or harsh environments, such as undersea connectors which can be repeatedly mated and demated underwater at great ocean depths. Such underwater connectors typically comprise a plug unit containing one or more contact probes and a receptacle unit containing an equivalent number of contacts or junctions for engagement with the contact probes, which extend into the receptacle unit when the units are connected together. Typically, the contacts or junctions are contained in a sealed chamber containing optically clear dielectric fluid, and the probes enter the container via one or more openings which are sealed when the units are separated. One major problem in designing such units is the provision of seals which will adequately exclude seawater and other contamination from the contact member even after repeated mating and demating, and also prevent fill fluid from leaking out of the chamber.
A number of different sealing mechanisms have been proposed in the past for achieving this objective. One such sealing mechanism has an opening into the contact chamber which comprises an elastomeric tubular entrance surrounded by an elastomeric sphincter which pinches the entrance closed upon itself when the plug and receptacle units are in an unmated condition. On mating, the contact probe is forced through the opening and the sphincter pinches against the probe to form a seal. Although this type of seal is successful in some cases, it does have disadvantages. One disadvantage is that this seal does not work well under all hostile conditions. Another disadvantage is that such seals tend to lose their xe2x80x9cmemoryxe2x80x9d after repeated mating and demating, so that they may fail to close completely, or may not close quickly enough to isolate the chamber from the surrounding environment when the units are demated. Another type of known seal mechanism comprises a piston which moves axially into the seal opening as the units are demated.
In some known underwater electrical connectors, such as that described in U.S. Pat. Nos. 4,795,359 and 5,194,012 of Cairns, tubular socket contacts are provided in the receptacle unit, and spring-biased pistons are urged into sealing engagement with the open ends of the socket assemblies. As the plug and receptacle units are mated, pins on the plug portion urge the pistons back past the contact bands in the sockets, so that electrical contact is made. However, this type of arrangement cannot be used in a straightforward way for an optical connector since the optical contacts must be able to engage axially for practical purposes.
Underwater electro-optical connectors are described in U.S. Pat. Nos. 4,616,900 and 4,666,242 of Cairns. In U.S. Pat. No. 4,666,242, the male and female connector units are both oil filled and pressure balanced. This device utilizes a penetrable seal element having an opening which pinches closed when the units are separated and seals against the entering probe when mated. Other known fiber-optic connectors have similar seals which are not suitable for use under some conditions and may tend to lose effectiveness after repeated mating and demating.
Other known seal mechanisms involve some type of rotating seal element along with an actuator for rotating the seal element between a closed, sealed position when the units are unmated, and an open position when the units are mated, allowing the contact probes to pass through the seal elements into the contact chambers. Such connectors are described for example, in U.S. Pat. Nos. 5,685,727 and 5,738,535 of Cairns. These overcome some of the reliability problems of penetrable seals for example, but can be too complex for miniaturized connectors.
It is an object of the present invention to provide a new and improved connector for making connections between optical fiber cables, electrical cables, or hybrid electro-optical cables in hostile environments, such as underwater.
According to the present invention, an underwater connector is provided which comprises a plug unit having a forward end, a rear end, and a hollow body, a first member mounted in the hollow body and forming an internal chamber, the member having a resilient forward end portion having an opening communicating with the internal chamber, at least one probe contact member mounted in the chamber in alignment with the opening, a receptacle unit having a hollow body, a forward end, and a rear end and adapted for releasable mating engagement with the plug unit, a second member mounted in the hollow body of the receptacle unit and having an internal chamber and a resilient forward end portion having an opening communicating with the internal chamber, and at least one receptacle contact member in the chamber in alignment with the opening, the resilient forward end portions of the first and second members having forward end faces in face-to-face sealing engagement when the units are mated together, the plug and receptacle units each having an actuator acting in a seal closing direction for compressing the resilient end portion of the respective member to close and seal the respective opening when the units are unmated, and for opening the openings when the plug and receptacle units are mated together with the end faces in sealing engagement, whereby at least one of the probe and receptacle contact members can pass through the aligned openings in the resilient end portions of the members to engage the other contact member, the openings in the resilient end portions each having a cross section which is elongated in a direction transverse to the closing direction.
In an exemplary embodiment of the invention, the actuator is designed to act in a seal opening direction to force the member openings to open when the end faces are in sealing engagement. In one embodiment, the actuator has a shaped throat designed such that the resilient end portions of the members are constricted in the seal closing direction when the units are mated, forming an elongated shape with a slit-like closure. When the units are connected together, the members travel through the actuator throats into a position in which they are compressed in a perpendicular, seal opening direction, forcing the openings to open. The actuator throat may be of gradually tapering, oval shape in order to compress the resilient end portions and close the openings, with an adjacent region of circular cross section which will compress the outer ends of the elongated end portions and force them back into a circular shape, forcing the openings back into an open configuration. By elongating the seal opening in a direction transverse to the seal closing direction, it can more readily be compressed into a slit-like shape without bunching up of excess material at the ends of the slit. Such bunching up can be a problem since the seal end face will then no longer be flat and smooth. In an exemplary embodiment, the openings are generally eye-shaped, with pointed opposite ends.
Preferably, one of the actuators is slidably mounted in the respective body of a first one of the plug and receptacle units and movable between an extended position in which the tapered throat engages the respective member end portion to squeeze the opening shut, and a retracted position in which the throat is pushed back over the end portion and the adjacent portion forces the opening to open. The member in the other, second unit is also slidably mounted for movement between an extended position in which the resilient end portion is engaged in the actuator throat and the opening is squeezed shut, and a retracted position in which the resilient end portion is retracted from the actuator throat and forced to open by an adjacent, circular part of the actuator. In operation, the end of the second unit engages the slidable actuator in the first unit to push it back as the two units are secured together. At the same time, the end of the member in first unit engages the end of the retractable member in the second unit, pushing it back into the retracted position so that both member openings are forced open. The contact element in the second unit travels through the open ends of the members to contact the corresponding contact element in the first unit.
In one embodiment of the invention, each actuator has a through bore having a forward end, and an inwardly tapering throat portion extending up to the forward end to squeeze the opening of the resilient end portion of the respective first or second member into the sealed and closed condition. The throat portion is preferably of oval, tapering cross-section up the forward end, and has opposing flat sides for squeezing the respective opening into a slit-like closure. The throat portion on one unit may be formed integrally or secured in the hollow body of the unit, while the other unit has a separate throat member slidably mounted in the body and automatically moved into the extended position when the plug and receptacle units are separated. Instead of forming the actuator as an inwardly tapered, oval bore or throat, alternative actuator mechanisms such as leaf springs or the like may be provided for squeezing the openings shut.
The connector may be a single circuit connector with a single contact probe on one side for contact with a single contact on the other side, or may be a multiple contact connector with electrical, optical, or both electrical and optical contacts to form a hybrid elctro-optical connector. In the latter case, both the plug and receptacle units may have multiple members forming chambers for the respective contact elements, and actuators for squeezing the end portions of the respective members closed when the units are disconnected. Alternatively, multiple circuits could be grouped within one member which is opened and closed by a single actuator. In an exemplary embodiment, both electrical and optical contacts may be mounted in the same oil filled chamber of the first and second members.
In an exemplary embodiment of the invention, the plug and receptacle units each contain a base module which extends into the respective chamber and on which a set of electrical contacts and an optical contact unit are mounted. The chamber is oil-filled so that the contact faces are always immersed in oil. The optical contact units may each comprise a ferrule housing in which a plurality of optical fibers are terminated, each housing having an end face with plural optical contacts for engagement with corresponding contacts on a mating end face of the other housing when the plug and receptacle units are connected together. This arrangement allows more electrical power to be transmitted and also permits a larger number of optical fibers to be connected via a relatively small connector package.
The connector apparatus of this invention is suitable for various undersea applications, such as connection of undersea telecommunications cables, oceanography research applications, submarine systems, and the offshore oil and gas industry. The invention avoids the need for complex rolling seal or stopper arrangements for sealing the connector, and is of much simpler construction than previous underwater connectors. All that is required in this invention to seal all of the contacts is a simple opening in a resilient end portion of a contact chamber, which is pinched closed in one position, and pushed away from the pinching device and forced open in a second position.